It is Ms Suu Kyi's first official visit to Thailand since her party swept historic elections last year, after decades struggling for democracy.
Her tightly-controlled schedule allows little interaction with the media, seen by some as a way of avoiding difficult questions about the treatment of Rohingya Muslims, who are held in camps in apartheid-like conditions in Myanmar's west.
She will visit a seafood-processing district south of Bangkok, meeting some of the millions of migrant workers who prop up Thailand's seafood, agriculture, construction and service industries.
At least 1.5 million and perhaps as many as 4 million Myanmar citizens live and work in Thailand.
Thousands of them are expected to turn out today, to try to catch a glimpse of their widely-revered leader.
Low pay, lower status
Rights groups say migrant workers in Thailand — legal and otherwise — are vulnerable to unscrupulous officials, trafficking gangs and employment agencies who charge huge sums to get them poorly paid work.
Their low status also sees them treated with scorn and mistrust by many Thais.
"They all want to go home, but they are just waiting for the economic situation [in Myanmar] to improve significantly," explained Andy Hall, a migrant rights activist with an office in the port town.
While Ms Suu Kwi was the nemesis of Myanmar's generals throughout her quarter-century of struggle for democracy, the Nobel laureate will meet with the leader of the Thai junta in Bangkok on Friday.
Ms Suu Kyi is also not scheduled to visit any of the Thai centres holding hundreds of Rohingya boat migrants who have fled poverty and persecution.
Campaigners say her failure to throw her moral weight behind the stateless minority is a boon to Myanmar's Buddhist hardliners who loathe the Rohingya and say they are illegal immigrants.